Description #
In this video we go through the importance of why paints should be removed before tiling, and the various tiling errors that could occur when leaving a painted surface as is, instead of removing it.
Transcript #
0:04
Hi everyone and welcome to another episode of Prep, Set, Go. For those who have joined us
0:08
previously we've been looking at tiling applications on different surfaces,
0:13
and in this short episode we'll be covering tiling over painted surfaces. So, let's jump
0:17
right in. Tiling over painted surfaces is something you'll often come across,
0:22
particularly in renovation projects - but can also occur in construction - and there are many
0:27
different types of paints you might come across, including water based acrylics, PVA paints,
0:32
polyurethanes, epoxies, oil based enamels, bitumen paints, and paving paints to name a few. Now while
0:38
the chemical composition, physical attributes, and respective uses may all be different,
0:44
they generally share the same common requirement when it comes to tiling... and that is that they
0:49
should be removed. So that's all for today's episode we said it be brief, thanks for joining
0:54
us. Now we're just kidding. Now let's explore why this blanket rule of removing paints before
1:02
tiling is applicable. Now firstly unless otherwise specified, paints are generally not designed to
1:09
carry any loadings, they are standalone finishes designed to support their own weight. Tiling
1:14
systems that include the weight of the tiles, adhesive, and grout, add significant strain on
1:19
the paint to support these additional loadings when they simply haven't been engineered to do
1:24
so. So there's an obvious risk of delamination of the paint from the substrate under load. Secondly,
1:30
if the paint isn't adequately adhered to the substrate or if it has a weak adhesion profile,
1:35
it could compromise the bond between the tiles and the substrate. Because remember the strength of
1:40
the tile bond is reliant on adhesion of the paint to the substrate, and not the tile adhesive to the
1:45
paint. Thirdly, glossy or oil- based paints tend to have a low porosity, making them inherently
1:51
difficult to adhere to. This impacts the chemical or physical bond of the adhesive to the paint and
1:56
increasing the likelihood of the adhesive and tiles to de-bond. Special primers and roughening
2:01
of the surface may assist to achieve a key, but there are still the other points we've just
2:06
covered to consider. Compatibility of the adhesive with the paint must also be considered. Can the
2:12
alkaline nature of the tile adhesive chemically affect breakdown or weaken the paint? Similarly
2:18
with water-based acrylics and PVA's, these have very low water tolerance - so contact with the
2:23
wet tile adhesive could result in peeling, softening, and breaking down of the paint,
2:28
and again the delamination of the tiles. So in summary, whenever faced with a painted surface
2:35
to be tiled, understanding and evaluating the associated risks would demand that removal of the
2:40
paint back to a surface more suited and capable of supporting the adhesion of the tiled finish
2:46
to be the more safer and prudent option. Sure it may require more work and added preparation,
2:51
but will eliminate potential risk and ensure the integrity and longevity of
2:56
the tiling system. Thanks for joining us on this episode, keep your feedback and comments coming,
3:00
we love hearing from you. And remember to like and subscribe, we'll see you next time.
